1. Field of the Invention
The present invention relates to an X-ray imaging apparatus which displays X-ray images as TV images.
2. Description of the Related Art
An X-ray imaging apparatus comprises an X-ray tube for directing X rays onto a subject under examination, an image intensifier adapted to convert an X-ray image formed of X rays transmitted through the subject to an optical image, a television camera for picking up the optical image produced on the image intensifier and a television monitor for visually displaying a picture signal from the TV camera.
A conventional X-ray imaging apparatus utilizes a television camera using a pickup tube such as a vidicon or saticon. With such a TV camera, various noise components of the signal are large relative to the desired signal, thus reducing dynamic range. A dynamic range of 60-70 dB cannot be provided. As a result, the picture quality is deteriorated. Furthermore, the residual image effect is noticeable, and the resolution is reduced because of the broadening of the beams.